The explosive growth of the internet and slow progress in fully deploying internet protocol version 6 (IPv6) addressing has resulted in a challenge for a number of internet service providers (ISP). Many legacy and newer devices are only capable of supporting IPv4 addressing, despite exhaustion of such addresses since 2011. Consequently, ISPs are often required to provide service to a large number of customers by sharing only a limited number of allocated or available public IPv4 addresses. The exhaustion of IPv4 addresses has resulted in difficulties for ISPs to efficiently apply network address translation (NAT).
Many ISPs have adopted carrier grade NAT (CGN) in an effort to address this shortage of public IPv4 addresses. CGN can be generally implemented in two different ways, namely IP_address-to-IP_address translation (conventional NAT or 1:1 NAT) and network address port translation (NAPT). Conventional NAT uniquely translates each private IP address to a public IP address. Under NAPT, however, each private IP address is translated to one or more ports of a public IP address.
There are various complications associated with these solutions where IPv4 addressing is concerned. For example, conventional NAT is not always practical for an ISP because the number of customers requiring private IPv4 addresses typically exceeds the number of public IPv4 addresses available to the ISP. This has led ISPs to offer static IPv4 addresses to customers at a premium cost. NAPT can be impractical because certain applications and hardware assume that a unique public IP address has been assigned, and often will not work properly. Furthermore, certain customers require inbound initiated access from the internet to home devices (e.g., computers, security cameras, etc.) while at work or abroad.
ISPs that implement CGN utilize NAT routers that will often block inbound NAPT traffic at the gateway, which is well before the user's home router. In order for the port to be maintained through to the server, a conventional NAT must be performed by the NAT router. Furthermore, in order to allow internet initiated traffic to work via IPv4 addressing for user applications, conventional NAT is required, and the NAT Router must support inbound initiated connections to the Public IPv4 NAT address.
Based on the foregoing, there is a need for an approach for supplying 1:1 NAT to certain users without the need for costly static IP addresses.